SPI Driver for Enhanced Relay Control

SPIDER - TLE7231G

Serial Peripheral Interface (SPI)

Datasheet

22

Rev. 1.2, 2014-05-09

Figure 11

Daisy Chain Configuration

In the SPI block of each device, there is one shift register where one bit from SI line is shifted in each SCLK. The

bit shifted out can be seen at SO. After 8 SCLK cycles, the data transfer for one device has been finished. In single

chip configuration, the CS line must transit from low to high to make the device accept the transferred data. In

daisy chain configuration the data shifted out at device #1 has been shifted in to device #2. When using three

devices in daisy chain, three times 8 bits have to be shifted through the devices. After that, the MCS line must

transit from low to high (see Figure 12).

Figure 12

Data Transfer in Daisy Chain Configuration

9.3

SPI Protocol

The SPI protocol of the TLE7231G provides two registers. The input register and the diagnosis register. The

diagnosis register contains four pairs of diagnosis flags, the input register contains the input multiplexer

configuration. After power-on reset, all register bits are cleared to 0.

SI

76543

210

IN3

IN2

IN1

IN0

SI

device 1

SPI

SO

SI

device 2

SPI

SO

SI

device 3

SPI

SO

MO

MI

MCS

MCLK

SPI_DasyChain.emf

MI

MO

MCS

MCLK

SI device 3

SI device 2

SI device 1

SO device 3

SO device 2

SO device 1

time

SPI_DasyChain2.emf